Three types of polyurethane recovery technology

With the increasing use of polyurethane materials in the national economy, and the increasing use of polyurethane materials, the recycling of waste materials has also received increasing attention.

The waste polyurethanes mainly include the corner wastes of the production plants, mold overflow materials, polyurethane foams and elastomers in scrapped automobiles and refrigerators, waste shoe soles and used PU leather, and spandex used clothes. At present, there are mainly three methods for recycling polyurethanes: physical methods, chemical methods, and energy methods.

1. The chemical recovery technology of polyurethane means that the polyurethane resin degrades into components of low relative molecular mass under the action of a chemical degradation agent. Due to the different degradation agents used, there are many types of chemical degradation. Different types of degradation products have different degradation products and different physical and chemical properties and effects. Therefore, corresponding degradation agents and degradation processes can be used according to the purpose of use. The degradation reaction of polyurethane mainly includes alcoholysis, ammonialysis, pyrolysis, alkali hydrolysis, and phosphate ester. Each method has its own advantages and disadvantages, but in either case, the principle is to break a large number of urethane bonds, ester bonds, urea groups, and ether bonds contained in the polyurethane macromolecules to form a relative bond. A liquid mixture containing a polyester or polyether polyol or polyurethane polyol and a small amount of amine with a small molecular mass.

2. There are many reports and practical techniques in the physical method. The PU products produced by this method have poor performance and are only suitable for low-grade products. Energy recovery is to recover heat by incinerating the waste. This method will cause secondary pollution and is basically no longer used. When physical recovery methods are technically and economically limited, chemical recovery is required. Therefore, the chemical recovery of polyurethane has always been a hot topic and a direction of development for chemists.

3, recycling of polyurethane is undoubtedly beneficial to environmental protection and resource utilization, but the main issue is whether the recycling of waste polyurethane has economic benefits. Due to the large amount of polyurethane, and the recent high prices of raw materials, the prospects of its waste recycling market are promising, but the previously used recycling methods are generally not economical and are not widely promoted. Therefore, an economically viable recovery method is developed. Has become a hot topic in the industry.